Process for treating fibrous materials for paper making and other purposes



Patented Sept. '30, 1924.

* UNITED STATES PATENT OFFICE.

PROCESS 1'08 CHARLES WEYGANG, OF MAIDENHEAD, ENGLAND.

TREATING FIIBROUS MATERIALS FOB PAPER MAKING AND OTHER PURPOSES.

Io Drawing. Application filed June 9,

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Be itknown t at I, CHARLES Wartime, a subject of the King of Great Britain, residing at 102 Grenfell. Road, Maidenhead, Berks, England, have invented a new or Im-, proved Process for Treating FlbI'OllS Materials for Paper Makin and Other Puroses, of which the to cation. 0

This invention relates to a new or 1mproved process for treatin wheat straw, oat straw, and like material or paper making and other purposes.

In existin processes, utilizing straw and the like, it in only been possible to produce either a material of very poor strength, such as straw boards or a material super or in strength, and quality by very expensive methods and with an'excessive loss, whereas according to the present invention it is possible to produce a superior and tough paper with much less loss and at considerably less cost.

The present invention comprises essentiallytreating the straw with a solution of slacked caustic lime, mixed with mineral oil and an alkali salt. The straw is treated with the compound eitherby soaking it in the compound in a cold state or by boiling it with the compound preferably under low pressure.

The mass so obtained after treatment 1s readily reduced to pulp in the ordinary way and converted into paper by the usual processes, which form no part of the present invention.

In carrying this invention into practice, I take for instance 8 parts by weight of caustic lime which is slacked with water in the usual way and is then preferably diluted with water to the consistency of a thin paste.

To this thin paste is then added 1 to 4 f parts by'wei ght of a mineral oil, either a crude oil, an intermediate oil or a refined oil such as ordinary petroleum.

The oil is energetically mixed with the lime paste untilit is thoroughly combined. To this mixture is added from! to 8 parts of a salt of an alkali such as carbonate or sulphate of sodium, the preferable arrangement being; to first dissolve such sodium salt in water and then combine the solution'with the lime and oil mixture by thoroughly mixing together. I

owing is a speci-- the like,

1922. Serial No. 587,198.

The sodium salts employed may well be the natural deposits of sodium salts existing in Canada and elsewhere.

The straw is then. either thoroughly soaked in the prepared liquor for from 12 to 24 hours or longer oris' 3 to 6 hours-preferably under low pressure-with the said liquor.

In the cold or soaking process-which is the preferable one inasmuch as a stron er and better coloured fibre results besides eing a simpler and less expensive method and entailing the least loss of fibre-after the straw has been soaked for a sufiicient time, it is drained and piled in heaps for use as required. It may be left in such heaps for an indefinite period as it does not heat or rot and moreover the longer it is left the softer does it become. The liquor drained from the unboiled material may be used again for a fresh lot of material and may be so used continuously, addition of fresh liquor being made as required to make up the requisite bulk. When the original liquor has drained off as much as possible the steeped straw may be roughly rinse with water, and the resultant liquor is sufliciently strong for steeping fresh straw, producing a coarser but stronger fibre.

The treated material from either process is reduced to pulp in the ordinary way, it may be bleached according to usual processes and is converted into paper in any well known manner.

The practice employed in commercially Working the invention is to first out up the straw, in a chaff cutting machine or then place the cut straw into pits or vats containing the chemical liquor Where it is left for half an hour more or less. The mass is then conveyed by any suitable orm of mechanical conveyor to such a place as to allow the surplus liquor to drain awa into the pit or vat for use in treating fresli straw- The drained mass, piled in convenient heaps, is left for 24 to 48 hours or longer and is then roughly rinsed with water sprayed over the heaps, pulped and converted into paper in the ordinary paper makers plant.

The liquor resulting from the rinsing process is run into other pits or vats and is used for treating straw for ultimate con-v vers1on into strong coarse paper or boards.

boiled for from I In some cases a second rinsing of the mass may be carried out and the resultant liquor used for treating fresh straw.

It will be appreciated that because of the simplicity of the cold or nonboiled process above cscribed and which does not necessitate the use of costly plant or machinery, the straw may be treated at outlying places where it is grown and the treated mass collected and conveyed in bulk to a central paper making plant, thus rendering the invention particularly valuable in Canada for instance. where there is not only an abundance of clean straw,which at present is of little or no value and is destroyed by v burningbut in which extensive natural deposits of sodium salts are also available.

I declare that what I claim is 1. In a process for the treatment of straw to produce a paper making material, treating the straw with a chemical liquor comprising 8 parts by weight of caustic lime slacked and diluted with water to a paste, 1 to 4 palts by weight of a mineral oil such as petroleum and 4 to 8 parts of carbonate of soda, as set forth.

2. A process for the treatment of straw to produce a paper making material comprising cutting up the straw into convenient lengths, steeping the cut straw for a sufficient time to become more or less soaked usually half an hour or longer in a chemical liquor comprisin a solution of slacked caustic lime, minera oil and an aqueous solution of an alkali salt, draining away the liquor and piling the drained mass into heaps where it is allowed to remain for about 24 hours or longer and rinsin the mass with water before pulping, as set orth.

CHARLES WEYGANG. 

